Reforming hydrocarbons is important in many applications to produce fuels such as H2 and chemical intermediates such as synthesis gas (syngas), and olefins. Reforming has generally been accomplished either by steam reforming or steam cracking which involve reaction with H2O in endothermic processes or by partial oxidation, which involves reaction with O2 in exothermic processes. Conversion of methane to syngas by both processes is well established, and reactions of alkanes up to iso-octane have been demonstrated.
While steam reforming and steam cracking of higher alkanes, such as diesel fuel, can be accomplished under suitable conditions, the partial oxidation of higher alkanes presents several problems, such as flames during vaporization and mixing, soot formation associated with combustion of fuel-rich gases, and coke formation on reactor walls and on catalysts.
Currently there is considerable interest in reforming logistic fuels such as diesel and JP-8 (similar to kerosene and used as a military fuel) into light alkanes and especially H2 for devices such as fuel cells, which function either exclusively on H2 (the proton exchange membrane fuel cell) or which function best with H2 in the fuel (the solid oxide fuel cell). Since a major interest is in fuel cells for transportation vehicles, gasoline and diesel are essential fuels in the next generation of fuel cell vehicles.
There is also considerable interest in fuel reforming for pollution abatement in automotive applications with internal combustion engines. Reforming of gasoline or diesel into H2 and other small molecules creates a fuel that burns very efficiently, thus reducing or eliminating exhaust emissions of hydrocarbons, CO, and particulate matter. The abatement of NOx in diesel engines is especially difficult because, unlike a spark ignited gasoline engine in a lean burn environment there is insufficient H2, CO, and small hydrocarbons to react with NOx in the catalytic converter. Therefore, reforming part of the fuel and using it to react with NOx could be important in diesel emissions control.
There is a need in the art for a convenient and scalable process for the conversion of hydrocarbon fuels including alkanes, particularly higher alkanes, cyclic alkanes, and aromatics, which provide valuable intermediates and products, such as synthesis gas and α-olefins with relatively high selectivities.